This invention relates to a sentence generating method and system for generating sentences in a language such as Japanese or English from a semantic representation that has been inputted into the system. Further, the invention relates to an improvement in the sentence style generated when translating a sentence in a first language (Japanese, for example) into a sentence in a second language (English, for example), and more particularly, to a sentence generating method well suited for use in machine translation.
A sentence generating method conventionally adopted in machine translation entails analyzing an inputted sentence in a first language, converting this sentence into a semantic representation and generating a sentence in a second language from this semantic representation. In this conventional method of generating sentences, generally the process for sentence generation is a procedure in which, with regard to a given semantic representation, the word order of a sentence is decided in accordance with grammatical rules, surface words and phrases are selected, and the selected surface words and phrases (expressions) are outputted.
However, since this conventional sentence generation process involves generating a partial sentence from the entirety of a sentence, one cannot take a survey of the whole while such partial generation is in progress. Accordingly, even if part of a sentence is capable of being generated correctly with the conventional approach, a disadvantage is that no consideration is given to the balance of the overall sentence.
For the foregoing reason, contradictions and unnatural wording can occur as a sentence is constructed in accordance with the conventional sentence generating method, and there are cases where sentences that are difficult to comprehend are generated, even though the sentences may not possess any grammatical errors. In particular, when a sentence in a second language generated and outputted according to the conventional method in a machine translating system is not in the native language of the system user, the user is not likely to notice that the outputted sentence is difficult to understand. And even if the user should happen to notice, a high level of linguistic knowledge and proficiency would be required in order to know which portions of the sentence should be revised and in what manner. Moreover, the user would be subjected to a considerable burden if actually required to revise outputted sentences frequently.